Any bearing surface that is to be used in an electroplating environment must be so constructed so that flakes, dust particles, lubricants, or the like from the bearing are kept out of the plating bath. To this end, the best result would be obtained through a bearng assembly which could operate free of unwanted particles such as lubricants, dust particles, flakes, or the like. Particles from a bearing assembly or other adjacent environmental origins stand the possibility, if deposited into the bath, of turning the characteristics of the entire electrolysis bath, plugging holes improperly in articles to be plated in the bath, or forming a foreign substance on the surface to be plated whereby plating cannot be properly achieved. Such is particularly true in the plating or printed circuit boards to which environment this invention is particularly applicable.
In the past, plating equipment had been furnished with friction type bearings having wear pads of a plastic material. The plastic material did not require lubrication. However, there would inevitably be a slight dust condition distributed into the air as the pad would wear through repetitive cycles of operation. This dust would float on the surface of, or into the plating solution and could contaminate the holes of the printed circuit boards being coated. Any metal that might wear from such bearing adjacent the plastic pads could contaminate and turn the entire solution to an undesirable characteristic.
Other bearings commonly used in electroplating environments included those with the moving bearing element contacting, or submerged in, a lubricating solution. While it is possible to encase the solution to some limited degree, the chance always existed that errant portions of the solution would enter the electroplating solution in the bath or tank. Further, as the lubricating solution became depleted replacement of the depleted portion would be required. When this was done as by manual means or any mechanical means the risk was further created of improperly depositing a quantity of lubricating solutions into the bath.
To overcome these deficiences the bearing assembly of the instant invention was devised which resulted in a bearing assembly requiring no lubrication and with the moving parts or elements so constructed and arranged so that flakes or chips would not be generated during repeated cycles of operation.
It is therefore an object of the instant invention to overcome the deficiences of the prior art through an improved bearing assembly.
Another object of the instant invention is a bearing assembly which is easily constructed; or repaired and which has easily replaceable parts.
Another object of the instant invention is a low cost bearing which is self-centering even by an unskilled operator.
Another object of the instant invention is a bearing assembly free of lubricating fluids and which will not flake, chip, or otherwise distribute unwanted particles into the environment.